Has anyone ever have or had their setup were the scanner was power by the computer power supply?

We have a couple of these...the computer has 12V available inside and can supply power to more than a few scanners. We have around 8 on one computer in one installation. It's a more economical way to go since the computer needs to always be up anyway. Just be sure to use a voltmeter and make sure you have the proper +12V and ground wires - and bring them out (drill a hole if you need to) through a rubber grommet.